1. Field of the Invention
This invention relates to portable, powered tools and, more particularly, to a tool having an elongate housing that is engageable and repositionable by a user to controllably situate a working component at an end of the housing.
2. Background Art
There is a multitude of portable, powered tools that are built around an elongate housing through which a user can extend the reach of a working component at an end of the housing. This tool design is common in the landscaping industry, for which tools are offered with many different capabilities. For example, the working component may incorporate a rotary, flexible trimmer line, an endlessly moving cutting chain, a reciprocating brush cutting blade(s), etc.
The elongate housing may be made with a fixed length or a variable length, with the latter commonly achieved through a telescoping connection of housing parts. With the tool incorporating a rotary flexible trimmer line, the user is allowed, through this construction, to stand upright upon a subjacent surface and comfortably cut and trim grass at that surface.
With the tool incorporating a moving cutting chain, the elongate housing permits an extended reach of the working component/chain on the tool, as to cut limbs at a relatively significant height without requiring the use of lifts or ladders. The same advantages are afforded by this design in the event that the working component incorporates one or more moving/reciprocating cutting blades, or other types of mechanism commonly used to trim bushes and cut other vegetation.
To facilitate safe and controlled operation with these tools, it is important that a user be able to positively lift and support the tool as well as reposition it to strategically place the working component precisely at different locations where an operation is to be performed.
It is also important that the tools be supportable by a user in operation in a manner whereby the user is not awkwardly positioned and does not suffer fatigue after extended use periods.
With all of the different tool designs, it is also critical that, in addition to supporting the tool in use, the user be able to conveniently control the speed of a drive for the tool.
One exemplary tool structure built upon an elongate housing is shown in U.S. Pat. No. 4,953,294, to Hans-Peter Dohse. In this design, a handle assembly branches away from an elongate housing and defines separate grips that can be grasped, one each, in the separate hands of a user. One of the grips is designed to double as a throttle control. The grip is turned around an axis to vary the speed of the associated drive.
This tool has a significant moment arm between the grips and the lengthwise center of gravity for the tool. Thus, after extended use, the user may be prone to fatiguing.
Also, by reason of offsetting and spacing the grips, the user is required to support and manipulate the tool with the arms extended somewhat awkwardly. This also may lead to fatigue and may additionally diminish the degree of control that the user has as he/she attempts to precisely place the working component of the tool during an operation.
Further, this tool suffers from the limitation that it is designed to be held by a user in essentially one orientation. Field conditions may require that a user awkwardly change the orientation from that for which it is designed.
For more positive control, tools built around elongate housings have been made with grips thereon that are surrounded by one or both hands of a user. An example of this design is shown in U.S. Pat. No. 6,182,367, to Jerzy Janczek. With one of the user's hands firmly surrounding the lengthwise housing axis, and the other hand grasping a spaced handle, the tool may be positively supported and repositioned.
With this design, one grip has, adjacent thereto, a throttle trigger that is repositioned by a pivoting movement through one or more fingers on the user's one gripping hand. The trigger of this type operates typically through a cable that shifts in response to the trigger movement.
This design also contemplates that the user will grasp the tool for operation primarily in one specific orientation. If the orientation of the working component is required to be changed, the user may be left with the options of gripping the tool in a manner not intended by its design, or awkwardly repositioning his/her body to place the working component in the desired operating orientation. In the former case, the ability to comfortably support the tool and at the same time properly operate the throttle may be compromised. This could lead to user fatigue and, potentially to an injury, if appropriate safeguards are not taken.
The industry continues to seek out designs for such tools that are safely and comfortably operable, and that afford versatility in terms of how they can be controllably repositioned in use.